How do I keep contamination out when inoculating grain?

Work in a still air box, wipe everything with 70% isopropyl, and flame-sterilise a needle before and after use. Let sterilised jars cool fully before injecting, keep the lid off for as little time as possible, and inject through a self-healing port or under micropore tape. Clean clothes, tied-back hair, and slow, deliberate movements all cut the airborne spores that cause most failures.